Infrared Conversion Canon 40D

I have a Canon 40D that was converted to Infrared a year ago by Life Pixel in WA. Since then I haven’t been capturing images with decent sharpness. I saw hundreds of images on the internet and they all look sharper than mine. Actually I can see the difference even at small sizes. My biggest problem is that the focus is always not satisfactory mostly shifted to the background subject. This becomes even more evident when shooting landscape or subjects at a distance of 20 feet or more. Life Pixel said that they calibrated my camera’s focusing to 50mm lens as a default. I didn’t send any lens along with my camera at the time when they converted my camera to infrared. But I found that specific 50mm lens and use that all the time. But the images are always blurry. It took me almost a year to finally convince myself that the problem is not in me or the lens, but in the camera. Most likely Life Pixel didn’t do a good job.

Although it is already costing over my budget, I am going to send my camera again in order to recalibrate my focusing. This time I am not going to Life Pixel again. They were extremely reluctant to accept the focusing problem and to give me a discount. I am a little confused about certain issue. I contacted Precision Camera and Kurt’s Camera Repair. Kurt’s Camera Repair told me that once the infrared focusing is set right on one lens, it works on almost any lens. Is that true? But Precision Camera said that they would calibrate at 24mm on my 24-205 mm lens in order to get the best use of the lens.

So I would like to get an answer from those who have an experience on this matter.
Is Canon 40D a decent camera to convert to dedicated infrared?

Is Canon 24-105mm f4L lens a good choice to calibrate the infrared focusing with my camera?
Do you know a reliable infrared conversion service?